Field of the Invention
The present invention relates to a machining method of a package substrate having light emitting diodes (LEDs) or other chips sealed thereon.
Description of the Related Art
When LEDs or other chips are packaged, a plurality of device chips are arranged on a front face of a ceramic substrate made, for example, of Al2O3 first, and a front face side of this ceramic substrate is coated with a light-transmitting mold resin, thus forming a package substrate. A plurality of device packages, each having a device chip packaged, can be obtained by dividing the package substrate along scheduled division lines (streets) set up between adjacent device chips.
The above division of a package substrate is conducted, for example, by a method based on abrasion using laser beams. However, this method highly likely results in degraded device chip quality due to sticking of a molten material, produced by abrasion, to a rear face side of the ceramic substrate. For this reason, a method is proposed that forms grooves along scheduled division lines on the rear face side of the ceramic substrate to accommodate the molten material, before the package substrate is machined (refer, for example, to Japanese Patent Laid-Open No. 2010-172900).